Pesticide Residue Rapid Extraction from Ginseng Tea Using a Modified Luke Method for GC–MS

Rapid and Sensitive Detection of Pentachloronitrobenzene by Surface-Enhanced Raman Spectroscopy Combined with Molecularly Imprinted Polymers

Molecularly imprinted polymers (MIPs) specifically targeting pentachloronitrobenzene (PCNB) and containing silver nanoparticles have been prepared by free radical polymerization reaction using methyl methacrylate (MMA) as a functional monomer, PCNB as a template molecule, 1,4-butanedioldimethacrylate as a cross linker, lauroyl peroxide (LPO) as an initiator, and the silver nanoparticles with the best surface-enhanced Raman scattering (SERS) effect as SERS enhancement materials. Our results indicated that MIPs specifically recognize PCNB from complex matrices. The intensity of the PCNB characteristic peak was proportional to the concentration, with a linear range of 0.005 to 0.15 μg/mL and a limit of detection of 5.0 ng/mL. The recovery rates and relative standard deviation for the detection of PCNB spiked in the rice samples were from 94.4% to 103.3% and from 4.6% to 7.4%, respectively. The experimental results are consistent with those by the GC-MS method, indicating that the rapid detection of PCNB in food matrices by SERS-MIPs is reliable. In view of the insolubility of PCNB in water, oil-soluble silver nanoparticles were synthesized which can be expanded to detect oil-soluble toxic substances. For the first time, the proposed method provides a point-of-care and cost-effective tool for rapidly detecting PCNB in food matrices with high sensitivity and selectivity by employing SERS-MIPs method.

A comparison of the effectiveness of QuEChERS, FaPEx and a modified QuEChERS method on the determination of organochlorine pesticides in ginseng

This study provides a review of methods used in the determination of organochlorine pesticides (OCPs) in ginseng and compares the effectiveness of three extraction methods (Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS), a modified QuEChERS and a Fast Pesticide Extraction (FaPEx)) in the analyses of 20 OCPs in ginseng root samples. For each method, sample mass, solvent volume and sorbent mass were varied to identify the optimum combination to effectively isolate analytes of interest from the complex sample matrix. Extracts were analyzed using the gas chromatography-μ-electron capture detector (GC-μ-ECD), and confirmatory analyses performed by gas chromatography-tandem-mass spectrometry (GC-MS/MS). Eighteen out of 20 OCPs spiked onto in-house prepared ginseng samples produced acceptable recoveries (51-156%) when extracted using QuEChERS and FaPEx. All 20 analytes, including dichlorodiphenyldichloroethane (p, p'- DDD) and dichlorodiphenyltrichloroethane (o, p'-DDT), produced acceptable recoveries (51-129%) with the use of a modified QuEChERS method. The applicability of the modified QuEChERS method was demonstrated through the analysis of ginseng samples grown in endosulfan-treated soil. The samples were analyzed by both GC-μ-ECD and GC-MS/MS with no significant difference identified in the results of each analytical method. This study highlights the applicability of the modified QuEChERS method, in combination with GC- μ-ECD, to determine organochlorine pesticides in ginseng. This may be especially useful for laboratories in developing countries and less advanced institutions without access to MS/MS instrumentation.

Changes of Ginsenoside Composition in the Creation of Black Ginseng Leaf

Ginseng is an increasingly popular ingredient in supplements for healthcare products and traditional medicine. Heat-processed ginsengs, such as red ginseng or black ginseng, are regarded as more valuable for medicinal use when compared to white ginseng due to some unique less polar ginsenosides that are produced during heat-treatment. Although ginseng leaf contains abundant ginsenosides, attention has mostly focused on ginseng root; relatively few publications have focused on ginseng leaf. Raw ginseng leaf was steamed nine times to make black ginseng leaf using a process that is similar to that used to produce black ginseng root. Sixteen ginsenosides were analyzed during each steaming while using high-performance liquid chromatography (HPLC). The contents of ginsenosides Rd and Re decreased and the less polar ginsenosides (F2, Rg3, Rk2, Rk3, Rh3, Rh4, and protopanaxatriol) enriched during steam treatment. After nine cycles of steaming, the contents of the less polar ginsenosides F2, Rg3, and Rk2 increased by 12.9-fold, 8.6-fold, and 2.6-fold, respectively. Further, we found that the polar protopanaxadiol (PPD) -type ginsenosides are more likely to be converted from ginsenoside Rg3 to ginsenosides Rk1 and Rg5 via dehydration from Rg3, and from ginsenoside Rh2 to ginsenosides Rk2 and Rh3 through losing an H₂O molecule than to be completely degraded to the aglycones PPD during the heat process. This study suggests that ginseng leaves can be used to produce less polar ginsenosides through heat processes, such as steaming.